1. Field of the Invention
This invention relates generally to the determination of the deviation of a body position from a horizontal plane and, more particularly, to apparatus for measuring the angle of deviation from a horizontal plane as defined by the gravitation field, the apparatus having an output signal suitable for input to electronic devices.
2. Discussion of the Related Art
One method for determining the deviation of a body position from a horizontal position is to provide a suspended apparatus, such as a pendulum, coupled to the body for which deviation from a reference direction is desired. When the body position is at an angle relative to the reference plane, then the pendulum is positioned at an angle to the member. The deviation of the perpendicular for the equilibirum position can be measured by several techniques, such as detection of the interruption of a beam of radiation or by other position sensing apparatus. In general however, such apparatus is not suitable for directly providing signals for an electronic data processing system.
Similarly, it is known in the related art to use at least one gyroscopic device to determine a reference plane and to rely on the conservation of angular momentum and a minimization of friction to detect the deviation from the reference plane. Similarly, gyroscopic devices have been designed using a laser apparatus in which the changes in the standing wave produced by the laser can be analyzed and a rotation in space can be determined. In both the mechanical and the laser gyroscopic devices, the apparatus is expensive, extremely sensitive and requires a skilled adjustment. In addition, the sensing of the deviation from the original position requires a sophisticated detection apparatus.
A need was therefore felt for a device that could be manufactured inexpensively, would provide a measure of the deviation of a body from a (horizontal) reference plane and; in addition, would provide an output signals capable of direct application to a data processing system.